Hoopla wants to make borrowing material from a library as convenient as streaming content on the web. The company, launching to the public today after several months in beta, offers patrons of participating libraries access to on-demand streaming movies and TV shows, as well as audiobooks and music that can be streamed or downloaded. There’s no waiting, and patrons don’t have to remember to return the digital materials: After a set period of time, they expire. Titles can be streamed on Hoopla’s website or its iOS and Android apps. The service launches at a time when libraries are increasingly making ebooks available to patrons. Seventy-six percent of U.S. public libraries offered access to ebooks in 2012. But offering access to other types of digital materials is still fairly new.